#!/bin/bash

# -------------------------------------------------------------------------- #
# Copyright 2002-2016, OpenNebula Project, OpenNebula Systems                #
#                                                                            #
# Licensed under the Apache License, Version 2.0 (the "License"); you may    #
# not use this file except in compliance with the License. You may obtain    #
# a copy of the License at                                                   #
#                                                                            #
# http://www.apache.org/licenses/LICENSE-2.0                                 #
#                                                                            #
# Unless required by applicable law or agreed to in writing, software        #
# distributed under the License is distributed on an "AS IS" BASIS,          #
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   #
# See the License for the specific language governing permissions and        #
# limitations under the License.                                             #
#--------------------------------------------------------------------------- #

# snap_create host:parent_image snap_id vmid ds_id

SRC=$1
SNAP_ID=$2
VMID=$3
DSID=$4

if [ -z "${ONE_LOCATION}" ]; then
    TMCOMMON=/var/lib/one/remotes/tm/tm_common.sh
    DATASTORES=/var/lib/one/datastores
else
    TMCOMMON=$ONE_LOCATION/var/remotes/tm/tm_common.sh
    DATASTORES=$ONE_LOCATION/var/datastores
fi

DRIVER_PATH=$(dirname $0)

. $TMCOMMON

SRC_PATH=$(arg_path $SRC)
SRC_HOST=$(arg_host $SRC)

#-------------------------------------------------------------------------------
# Get Image information
#-------------------------------------------------------------------------------

DISK_ID=$(basename ${SRC} | cut -d. -f2)

XPATH="${DRIVER_PATH}/../../datastore/xpath.rb --stdin"

unset i j XPATH_ELEMENTS

while IFS= read -r -d '' element; do
    XPATH_ELEMENTS[i++]="$element"
done < <(onevm show -x $VMID| $XPATH \
                    /VM/TEMPLATE/DISK[DISK_ID=$DISK_ID]/SOURCE \
                    /VM/TEMPLATE/DISK[DISK_ID=$DISK_ID]/CLONE )

DISK_SRC="${XPATH_ELEMENTS[j++]}"
CLONE="${XPATH_ELEMENTS[j++]}"

SYSTEM_DS_PATH=$(dirname ${SRC_PATH})

SYSTEM_DS_DISK_PATH="${SYSTEM_DS_PATH}/disk.${DISK_ID}"
SYSTEM_DS_DISK_PATH_SHORT="disk.${DISK_ID}"

if [ "$CLONE" = "YES" ]; then
    DISK_PATH="${SYSTEM_DS_DISK_PATH}"
    DISK_PATH_SHORT="$(basename ${SYSTEM_DS_DISK_PATH})"
else
    DISK_PATH=$DISK_SRC
    DISK_PATH_SHORT=$DISK_PATH
fi

NEXT_SNAP_ID=$(($SNAP_ID+1))

SNAP_DIR="${DISK_PATH}.snap"
SNAP_DIR_SHORT="${DISK_PATH_SHORT}.snap"

SNAP_PATH="${SNAP_DIR}/${NEXT_SNAP_ID}"
SNAP_PATH_SHORT="${SNAP_DIR_SHORT}/${NEXT_SNAP_ID}"

SNAP_CMD=$(cat <<EOT
set -ex -o pipefail

mkdir -p "${SNAP_DIR}"

PREVIOUS_SNAP=\$(readlink $SYSTEM_DS_DISK_PATH)

cd "${SNAP_DIR}"
qemu-img create -f qcow2 -b "\${PREVIOUS_SNAP}" "${SNAP_PATH}"
ln -sf $SNAP_PATH_SHORT $SYSTEM_DS_DISK_PATH
EOT
)

ssh_exec_and_log "${SRC_HOST}" "${SNAP_CMD}" \
                 "Error creating snapshot ${SNAP_PATH}"

